The armchair Londoner

It was a beautiful sunny morning with lovely winter light. I planned to take a walk up to the park in the afternoon but had some work to get done first. Disappointingly, by the time I was ready to go out it had clouded over and started to drizzle. As a consequence I stayed in. No blip from the park. What could I do?
I bring you the armchair Londoner; my collection of London books...